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Free ACI Practice Questions

10 free, exam-style ACI Concrete Field Testing Technician Grade I (ACI) practice questions with answers and explanations. No signup required. Work through them below, then take the full free ACI practice test to study every exam domain.

Question 1

A technician is building a composite sample from a truck mixer and takes the first portion, then gets pulled away. What is the maximum time that may elapse between obtaining the first and the final portions of that composite sample?

  1. 15 minutes
  2. 5 minutes
  3. 10 minutes
  4. 30 minutes
Show answer & explanation

Correct answer: A - 15 minutes

Question 2

Fresh concrete is being discharged from a revolving-drum truck mixer at the job site. To obtain a representative sample, the technician should collect it:

  1. From the first concrete out of the chute, before it segregates
  2. As a single scoop from whatever point is most convenient
  3. From two or more portions taken during the middle of discharge
  4. From the last of the load, once the drum is nearly empty
Show answer & explanation

Correct answer: C - From two or more portions taken during the middle of discharge

Question 3

When performing the slump test, over what period of time must the technician raise the mold off the concrete?

  1. Slowly, over 15 to 20 seconds
  2. In one quick motion, under 1 second
  3. 10 ± 2 seconds
  4. 5 ± 2 seconds
Show answer & explanation

Correct answer: D - 5 ± 2 seconds

Question 4

Using the pressure method, a technician reads 6.0% on the air meter gauge. The aggregate correction factor for this mix has been determined to be 0.3%. What is the correct air content to report?

  1. 5.7%
  2. 6.3%
  3. 6.0%
  4. 0.3%
Show answer & explanation

Correct answer: A - 5.7%

Question 5

A mix is batched with a lightweight, highly porous aggregate. Which statement about measuring its air content is correct?

  1. The volumetric method (C173), since trapped air in the aggregate distorts a pressure reading
  2. The pressure method (C231), but with the applied gauge pressure raised to compensate for the aggregate
  3. The pressure method (C231), simply doubling the aggregate correction factor
  4. Either method, since both give the same result on any aggregate
Show answer & explanation

Correct answer: A - The volumetric method (C173), since trapped air in the aggregate distorts a pressure reading

Question 6

During the volumetric (roll-a-meter) test, the technician takes an initial reading, rolls the meter again, and takes a second reading. For the second reading to be accepted as the final result, the two readings must agree within:

  1. 0.50%
  2. 0.10%
  3. 0.25%
  4. 1.0%
Show answer & explanation

Correct answer: C - 0.25%

Question 7

A batch of concrete contains a total of 3,915 lb of materials. The measured density (unit weight) of the fresh concrete is 145.0 lb/ft³. What is the yield of the batch?

  1. 145.0 ft³
  2. 0.037 ft³
  3. 4,060 ft³
  4. 27.0 ft³
Show answer & explanation

Correct answer: D - 27.0 ft³

Question 8

A yield test returns a relative yield (Ry) of 0.98. What does this tell the technician about the batch?

  1. The batch produced slightly more concrete than designed
  2. The batch is slightly short of its designed volume
  3. The air content is exactly 2% too low
  4. The density was measured incorrectly and the test is void
Show answer & explanation

Correct answer: B - The batch is slightly short of its designed volume

Question 9

A technician needs to measure the temperature of fresh concrete in a wheelbarrow. For the reading to be valid, the temperature sensor must be:

  1. Held just below the surface for a quick reading
  2. Pressed against the bottom of the container
  3. Surrounded by at least 1 in. of concrete in all directions
  4. Surrounded by at least 3 in. of concrete in all directions
Show answer & explanation

Correct answer: D - Surrounded by at least 3 in. of concrete in all directions

Question 10

Standard-strength cylinders have been molded at the job site. While they wait to be transported to the lab, what is the required initial curing temperature range?

  1. 60 to 80°F (16 to 27°C)
  2. 50 to 70°F (10 to 21°C)
  3. 68 to 78°F (20 to 26°C)
  4. 70 to 90°F (21 to 32°C)
Show answer & explanation

Correct answer: A - 60 to 80°F (16 to 27°C)

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